/**
 *!
 * \file        algo_base64.c
 * \version     v0.0.1
 * \date        2020/04/27
 * \author      Bean(notrynohigh@outlook.com)
 *******************************************************************************
 * @attention
 *
 * Copyright (c) 2020 Bean
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *******************************************************************************
 */

/*Includes ----------------------------------------------*/
#include "algorithm/inc/algo_base64.h"

#include <string.h>
/**
 * \addtogroup ALGORITHM
 * \{
 */

/**
 * \addtogroup BASE64
 * \{
 */

/**
 * \defgroup BASE64_Private_TypesDefinitions
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup BASE64_Private_Defines
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup BASE64_Private_Macros
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup BASE64_Private_Variables
 * \{
 */
#define BASE64_PAD '='
#define BASE64DE_FIRST '+'
#define BASE64DE_LAST 'z'

/* BASE 64 encode table */
static const char base64en[] = {
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
    'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
};

/* ASCII order for BASE 64 decode, 255 in unused character */
static const uint8_t base64de[] = {
    /* nul, soh, stx, etx, eot, enq, ack, bel, */
    255, 255, 255, 255, 255, 255, 255, 255,

    /*  bs,  ht,  nl,  vt,  np,  cr,  so,  si, */
    255, 255, 255, 255, 255, 255, 255, 255,

    /* dle, dc1, dc2, dc3, dc4, nak, syn, etb, */
    255, 255, 255, 255, 255, 255, 255, 255,

    /* can,  em, sub, esc,  fs,  gs,  rs,  us, */
    255, 255, 255, 255, 255, 255, 255, 255,

    /*  sp, '!', '"', '#', '$', '%', '&', ''', */
    255, 255, 255, 255, 255, 255, 255, 255,

    /* '(', ')', '*', '+', ',', '-', '.', '/', */
    255, 255, 255, 62, 255, 255, 255, 63,

    /* '0', '1', '2', '3', '4', '5', '6', '7', */
    52, 53, 54, 55, 56, 57, 58, 59,

    /* '8', '9', ':', ';', '<', '=', '>', '?', */
    60, 61, 255, 255, 255, 255, 255, 255,

    /* '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', */
    255, 0, 1, 2, 3, 4, 5, 6,

    /* 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', */
    7, 8, 9, 10, 11, 12, 13, 14,

    /* 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', */
    15, 16, 17, 18, 19, 20, 21, 22,

    /* 'X', 'Y', 'Z', '[', '\', ']', '^', '_', */
    23, 24, 25, 255, 255, 255, 255, 255,

    /* '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g', */
    255, 26, 27, 28, 29, 30, 31, 32,

    /* 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', */
    33, 34, 35, 36, 37, 38, 39, 40,

    /* 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', */
    41, 42, 43, 44, 45, 46, 47, 48,

    /* 'x', 'y', 'z', '{', '|', '}', '~', del, */
    49, 50, 51, 255, 255, 255, 255, 255};

/**
 * \}
 */

/**
 * \defgroup BASE64_Private_FunctionPrototypes
 * \{
 */

/**
 * \}
 */

/**
 * \defgroup BASE64_Private_Functions
 * \{
 */

/**
 * \}
 */

/**
 * \addtogroup BASE64_Exported_Functions
 * \{
 */

uint16_t base64_encode(const uint8_t *in, uint16_t inlen, char *out)
{
    int      s;
    uint16_t i;
    uint16_t j;
    uint8_t  c;
    uint8_t  l;

    s = 0;
    l = 0;
    for (i = j = 0; i < inlen; i++)
    {
        c = in[i];

        switch (s)
        {
            case 0:
                s        = 1;
                out[j++] = base64en[(c >> 2) & 0x3F];
                break;
            case 1:
                s        = 2;
                out[j++] = base64en[((l & 0x3) << 4) | ((c >> 4) & 0xF)];
                break;
            case 2:
                s        = 0;
                out[j++] = base64en[((l & 0xF) << 2) | ((c >> 6) & 0x3)];
                out[j++] = base64en[c & 0x3F];
                break;
        }
        l = c;
    }

    switch (s)
    {
        case 1:
            out[j++] = base64en[(l & 0x3) << 4];
            out[j++] = BASE64_PAD;
            out[j++] = BASE64_PAD;
            break;
        case 2:
            out[j++] = base64en[(l & 0xF) << 2];
            out[j++] = BASE64_PAD;
            break;
    }

    out[j] = 0;

    return j;
}

uint16_t base64_decode(const char *in, uint16_t inlen, uint8_t *out)
{
    uint16_t i;
    uint16_t j;
    uint8_t  c;

    if (inlen & 0x3)
    {
        return 0;
    }

    for (i = j = 0; i < inlen; i++)
    {
        if (in[i] == BASE64_PAD)
        {
            break;
        }
        if (in[i] < BASE64DE_FIRST || in[i] > BASE64DE_LAST)
        {
            return 0;
        }

        c = base64de[(uint8_t)in[i]];
        if (c == 255)
        {
            return 0;
        }

        switch (i & 0x3)
        {
            case 0:
                out[j] = (c << 2) & 0xFF;
                break;
            case 1:
                out[j++] |= (c >> 4) & 0x3;
                out[j] = (c & 0xF) << 4;
                break;
            case 2:
                out[j++] |= (c >> 2) & 0xF;
                out[j] = (c & 0x3) << 6;
                break;
            case 3:
                out[j++] |= c;
                break;
        }
    }

    return j;
}

/**
 * \}
 */

/**
 * \}
 */

/**
 * \}
 */

/************************ Copyright (c) 2020 Bean *****END OF FILE****/
